1. Field of the Invention
The present invention relates to an apparatus for manufacturing a semiconductor device and more particularly, to an apparatus using plasma.
2. Discussion of the Related Art
Due to a development in the semiconductor industry, a semiconductor device has pursuit high capacity and various functions, and it is required to integrate more circuits in limited region. Thus, technique for treating wafers has been researched and developed to make patterns extremely fined and highly integrated. To realize such a semiconductor device, methods using plasma has been widely used in processes for manufacturing the semiconductor device, such as depositing and etching of a thin film.
The apparatus using plasma will be explained with reference to attached drawings.
FIG. 1A is a schematic view of showing an apparatus for manufacturing a semiconductor device in the related art, and FIG. 1B is an enlarged view of the portion “A” of FIG. 1A. The portion “A” corresponds to where one end of a helium line is inserted into fixed parts of a lower electrode and a chuck base.
In FIGS. 1A and 1B, the apparatus includes a chamber 10 and an upper electrode 20, a lower electrode 30, a chuck base 40 and an electrostatic chuck 50 therein. The upper electrode 20 and the lower electrode 30 are spaced apart at upper and lower parts of the chamber 10 and facing each other. The upper electrode 20 and the lower electrode 30 are supplied with matched high frequency power, for example, radio frequency (RF) power, from the outside, and form plasma in the chamber 10. The electrostatic chuck 50 is disposed on the lower electrode 30, and settles a wafer W by electrostatic force. Here, the chuck base 40, which is interposed between the electrostatic chuck 50 and the lower electrode 30, protects and supports the electrostatic chuck 50. Moreover, the chuck base 40 provides high frequency power and generates static electricity. An insert 61 at one end of a helium line 60 is put in and passing through fixed parts of the lower electrode 30 and the chuck base 40 to supply an insert gas, such as helium (He) gas, into a gap between the wafer W and the electrostatic chuck 50. At this time, the insert 61 is disposed so that the helium gas might be provided into an injection hole of the electrostatic chuck 50.
The helium gas, which functions as an intermediary, disperses heat transmission between the lower electrode 30 and the wafer W, and properly maintains the temperature of the wafer W by cooling while a process for the wafer W, such as depositing and etching, is going on. The helium gas is injected through the helium line 60 from a helium gas source part (not shown) of the outside.
Thus, when the process is going on, matched high frequency power is applied to the upper electrode 20 and the lower electrode 30, thereby forming plasma. At this time, high frequency power of direct current is applied to the electrostatic chuck 50, and static electricity is generated. Simultaneously, electric field of a vertical direction in the context of the figure is formed in the helium line 60 for supplying helium gas by the electrostatic chuck 50 and the chuck base 40 supporting the electrostatic chuck. 50. Therefore, at a part of the chuck base 40, where one end of the helium line 60 is inserted, arc helium plasma may be formed. The arc helium plasma causes unstable matching of high frequency power at the upper and lower electrodes, static electricity and direct current voltage, and the wafer W may float. Like this, the arc helium plasma has evil effects on the process.
To solve the problem, a ceramic of an insulator has been used as the insert of the helium line.
FIGS. 2A and 2B schematically show another helium line according to the related art. In FIGS. 2A and 2B, to prevent plasma around the insert of the helium line, the insert 61 may be made of a ceramic, and the insert 61 may include a plurality of fine tubes as shown in FIG. 2A or a bended fine tube as shown in FIG. 2B. However, fine particles are still attached to the treated surface of the ceramic insert, and thus the surface of the wafer may be damaged. In addition, processing the ceramic insert is so hard that manufacturing costs may increase.